Whether contemplating a new car or getting your current car ready for the road, these tips will help you drive safely this winter.Try a Winter Driving Safety Quiz
Front, Rear, All, and Four Wheel Drive: Which one is best for winter travel?
In order from worst to best:
A rear wheel drive vehicle with an open differential can't put down power if one of the rear wheels starts slipping. Fortunately, these are only seen today on base model trucks and vans.
Most newer rear wheel drive vehicles have a limited slip differential. If one drive wheel starts slipping, power is redirected to the other wheel.
A front wheel drive powertrain gets better traction because the weight of the engine and transmission is over the drive wheels.
When engaged, a four wheel drive system sends power to every wheel. This even power distribution can get the vehicle unstuck when the front or rear wheels are in a place that they can't get traction. However, this also means they can't compensate for different wheel speeds when turning, which can make handling unpredictable on dry pavement.
An all wheel drive powertrain automatically adjusts power to each wheel, allowing for both the traction capabilities of 4WD and the predictable turning behavior of 2WD.
Just as important are electronics systems: ABS can keep the wheels from locking under braking, traction control can keep the vehicle from spinning out while moving from a start, and electronic stability control can keep power in check while making a turn. Having these systems will improve traction with any drivetrain.
Getting the Best Performance from Your Vehicle
There is nothing that improves winter driving more than the right set of tires: While all wheel drive and advanced computer aids will get a vehicle moving, its the ability of the tires to grip the road that determines stopping distances.
While all-season tires are far better than summer performance tires in the snow, they're a far cry from true winter tires. The "M + S" label found on many all season tires stands for "mud and snow," but all that means is they have a thick tread depth. After just 20% of the tread has worn off, these tires lose 80% of their grip on ice and snow.
Winter tires are more than just deep treads: the compound has a special compound that wicks away water created when the warm tire melts the ice it's riding on. The compound also stays pliable in very low temperatures, and is soft enough to handle the bumpy surfaces left behind by compacted snow.
For most drivers, studless winter tires are the best choice as they can handle slick roads without majorly compromizing dry surface performance. Studded tires have better ice performance, but they're terrible on dry roads, and are outlawed in many areas because they rapidly wear to road surfaces. A new category, winter performance tires, is biased more towards dry road performance. These are available in the low profile sizes popular on sports cars. Here's a helpful Winter Tire Decision Guide
There are a few more things you should consider when getting your car ready for winter travel:
Batteries take cold weather the hardest, losing 35% of their cranking power when it dips below freezing, and 50% once the temperature reaches 0 degrees Fahrenheit (-18 degrees Celsius.) While most new batteries are sealed "maintenance free" units, they can still benefit from having clean terminal contacts. If the battery is a few years old, take it into a parts store for a load test. If it doesn't pass, it's better to get a replacement now instead of being stuck in a parking lot.
For severe cold weather, you may need to switch to a lighter oil. The "W" on the label of multi-grade oils doesn't stand for "weight," it stands for "winter." These oils have been tested to flow at the rate in front of the W at freezing temperatures: A 5W30 oil will flow like a 5 weight oil when cold, thickening to a 30 weight oil once the engine is up to operating temperature. Information on the proper oil weight for winter temperatures will be listed in your owner's manual as well as a sticker underneath the hood.
The resistance of the engine's coolant to freezing is dependent of the age and quantity of antifreeze mixed in with the water. Temperature testing can be done at an auto shop, or with a floating ball gauge available at your local parts store.
Wiper fluid is key for keeping the windshield clear of water and road salt. Look for wiper fluid designed for cold use and avoid any that is marked "summer mix." Likewise, winter wiper blades are designed with joints that resist ice build-up and heavy duty low temperature rubber for the blade surface, helping them cut through windshield build-up at any temperature.